Fixed PHP4-compatibility problem in zc_install (NOTE: You shouldn’t be using PHP4 anyway!)

NOTE:
If you’re upgrading from v1.3.9a or b or c or d or e, you can simply update the files listed in the various “Changelog for v1.3.9b” and “c” and “d” and “e” in the /docs/ folder of the download zip.
(There are no database changes between v1.3.9a-b-c-d-e-f.)

If you’re upgrading from v1.3.8a or older versions, you need to follow the FULL upgrade instructions, also in your /docs/ folder

UPGRADE TIP:
You may have problems accessing your admin or storefront after installing the upgrade if you don’t first clear your browser cache and cookies and restart the browser.